Duxbury Mass-The prosecution’s case against is expected to focus heavily on the idea that the killings were planned and deliberate.
Prosecutors will try to convince jurors that she knew exactly what she was doing and understood it was wrong, despite the defense arguing she was suffering from severe postpartum psychosis and other mental illnesses at the time.
One of the biggest points the DA is expected to push is timing. Prosecutors have already argued that Clancy allegedly carried out the killings during the short window when her husband left the house to pick up food and medication. They’re also likely to focus on the use of exercise bands and the sequence of what happened involving all three children, arguing it showed methodical actions rather than confusion or complete detachment from reality.
The state has also had multiple psychiatric experts evaluate Clancy and appears prepared to directly challenge the insanity defense. Prosecutors are expected to argue that her actions afterward — including her suicide attempt — reflected guilt and awareness of what had happened, rather than someone completely unable to understand right from wrong.
The DA may also introduce internet searches, text messages, medical records, timelines, and her behavior leading up to the deaths to argue she was functioning and aware. Some reports have mentioned searches such as “what is a psychopath?” in the days before the killings, something prosecutors could use to suggest consciousness and intent.
Meanwhile, the defense is building its entire case around Clancy’s mental health. Her attorneys say she was suffering from postpartum psychosis, bipolar disorder with postpartum onset, severe mental illness, and that she may have been dangerously overmedicated with psychiatric drugs. Their argument is essentially that her mental state was so impaired she could not truly understand reality or the nature of her actions.
Her lawyers are also trying to split the trial into separate phases, so jurors would first decide the facts of what happened, and only afterward decide whether she was legally criminally responsible because of insanity.
Right now, legal analysts see this as an extremely difficult case for both sides. There’s little dispute about what happened physically — the real battle will be over Clancy’s mental state at the time. Massachusetts also has a very high legal standard for insanity defenses, meaning the defense faces a major challenge even with psychiatric experts supporting their claims.
The outcome could realistically go several ways. A jury could convict her outright, find her not guilty by reason of insanity, or land somewhere in between on certain charges depending on how they interpret the psychiatric evidence.
In the end, the case may come down to which side’s experts the jury believes, how convincing the medication and mental health evidence is, and whether jurors believe psychosis completely overrode her ability to understand reality. The emotional weight of the case — involving the deaths of three very young children — will also inevitably play a major role throughout the trial.
The trial is currently scheduled to begin July 20, 2026, in .
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